Deconstruction is a theory of criticism in which we question assumptions about identity and beliefs by discovering the assumptions upon which ideas are based.
In her book Bodies That Matter: On Discursive Limits of Sex, Judith Butler's main point is to assert that gender and body can be thought of separately because, as scholar Sara Salih phrases it in explaining Butler, "Gender is not something one is, it is something one does, an act, or more precisely, a sequence of acts, a verb rather than a noun" (Georgetown University, "On Judith Butler and Performativity"). One reason why Butler asserts this is because it can also be said that gender does not exist without social conditioning; therefore, if we tie gender to body, it would mean that body cannot exist outside of social conditioning, which Butler considers to be a fallacy. Butler elaborates further to say that gender is a repeated pattern in actions, not just actions in general. Butler's theory is best summed in her following statement found in her earlier book Gender Trouble:
Gender is the repeated stylization of the body, a set of repeated actions within a highly rigid regulatory frame that congeal over time to produce the appearance of substance, of a natural sort of being. (Ch. 1)
In this passage, she continues further to explain that we can deconstruct "the appearance of gender" into its actions.
Hence, in breaking down the understanding of gender into a set of repeated actions, Butler is using deconstruction. More specifically, Butler uses deconstruction to separate gender from body and then further uses deconstruction to identify what body truly is.
Butler uses a very complex deconstruction argument in her first chapter, titled "Bodies that Matter," in her book Bodies That Matter, in order to assert her new definitions of both body and gender. She begins by asserting that we need to deconstruct the understanding of matter in order to further deconstruct the understanding of body in a way that upholds feminist views. To deconstruct matter, she turns to Aristotle. Aristotle defined matter and soul as being inseparable because matter cannot be actualized, cannot be realized, without the existence of soul. She quotes Aristotle as saying in his De Anima that the question of "whether the soul and the body are one" can be dismissed because it is just as "meaningless to ask whether the wax and the shape given to it by the stamp are one, or generally the matter [hyle] of a thing and that of which it is the matter [byle]" (p. 32). She uses Aristotle to argue that "matter never appears," can never be separated from its schema, meaning "form, shape, figure, appearance, dress gesture, figure of syllogism, and grammatical form" (p. 32). Hence, for Aristotle, the soul of a thing is its form, the thing that actualizes its existence; for Aristotle, matter is its actualization, what it does, not what it is. She further uses Michel Foucault to identify soul as that which "inhabits him and brings him to existence" and to argue that there is a link between matter and power, that "'materiality' ... is power" (p. 34). Therefore, she uses both Aristotle and Foucault to deconstruct matter in order to understand matter in terms of what it does, not in terms of what it is. In terms of body and gender, we can understand body as matter and gender as form. Yet, though form and matter cannot be separated, the fact remains that form and matter are two very distinct beings. Therefore, she continues in her deconstruction to show how form can be seen as distinct from matter, or gender distinct from body.
She next uses Luce Irigaray and her discussion of Plato to argue that there is a distinction between form and matter; therefore, gender is not a part of body, and being feminine is not a part of body. However, she also criticizes Irigaray's conclusion that femininity is neither a part of form nor matter and instead argues that both genders are a part of form. But once we draw a distinction between form and matter, or gender and body, while also maintaining that they cannot be separated, we can say that gender is the form that gives life to the body, but gender is not what the body is; it's what the body does, just as matter is actualized by form.